Subrack with routing modules

ABSTRACT

A subrack has in addition to conventional modules a special routing module. The modules are detachably connected to the routing module via mutually identical bundles of optical fibers and multiple-plug connectors. Devices located outside the subrack are connected to the routing module. The assignment of the connections between the modules themselves, on the one hand, and between the modules and devices located outside the subrack, on the other hand, is carried out on the routing module.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject matter of the invention relates to a subrack foraccommodating modules, in which

the module subrack has a number of modules

each module is detachably connected to another module via an opticalfiber and a multiple-plug connector.

2. Description of Prior Art

A module subrack having the features specified is disclosed by EP0511779.

In a subrack, a plurality of modules are combined to form a mechanicallystable unit. Modules which have components receiving or transmittingoptical signals must be connected to other modules via optical fiberstransporting optical signals. In a case where the connections are madeby individual optical fibers, it is found that the production cost ishigh, for subracks having a different connection structure it beingnecessary for this structure to be taken into account and, in addition,there being a constant risk of transpositions. In a case where thewiring is carried out conventionally using bundles of optical fibers, itis disadvantageously found that the ends of the individual opticalfibers must, in general, be fed to different modules, with the resultthat the bundle of optical fibers has to be separated with a great dealof effort.

In the case of the subrack disclosed by EP 0511779, the optical outputelement of each module is connected to all the input elements of theother modules. This concept requires selection on the individual modulesof the information intended for them.

The application is based on the problem of indicating a particularconfiguration for the connections between the modules of a subrack whichis largely standardized, simple and can be produced free of errors, andin addition allows feeding only of the information which is intended forthe relevant module.

SUMMARY OF THE INVENTION

In the case of the subrack mentioned at the beginning, the problem issolved in that

the subrack has a routing module which is common to all the modules,

each module is detachably connected to the routing module via a bundleof optical fibers and a multiple-plug connector,

the routing module is designed in such a way that an assignment ofconnections is provided between the individual optical fibers of thebundles of optical fibers connected to the routing module.

The subject matter of the application accomplishes simple connectabilityof a module of the subrack in a single operation, whilst excludingtranspositions. Uniform connecting lines can be provided for differentsubracks for the connections between the modules and the routing module,the assignment of the individual wave-guides being provided solely bythe routing module. By means of exchanging the pluggably arrangedrouting module for a routing module having a different assignment of theindividual connections, a simple capability is provided for changing theassignment of the connections of the modules of a subrack. The subjectmatter of the application therefore accomplishes a standardization ofthe connections between modules for subracks having is differentconnecting functions, whereby the subrack can be prefabricated to a verylarge extent. The optical signals which are fed to the subrack and areforwarded by the subrack are fundamentally passed via two stages, thatis to say via the routing module and the relevant module, with theresult that the dynamic requirements of the input stage of the receiverof the optical signals are reduced in comparison with arrangements inwhich the optical signals are passed partly via only one stage andpartly via two stages.

In accordance with the present invention, a module subrack assembly isprovided that comprises a subrack that accommodates at least one routingmodule in addition to one or more conventional modules. Eachconventional module is connected to an input port of the routing moduleby a linking optical fiber bundle. Each linking fiber optical bundleincludes two ends, both of which are attached to multiple-plugconnectors. One multiple plug connector is attached to the conventionalmodule and the other multiple-plug connector is attached to an inputport of the routing module.

The routing module further includes one or more output ports which, inturn, accommodate a multiple-plug connector that is attached to anoutput optical fiber bundle. The routing module provides the connectionbetween an individual optical fiber of the linking bundle to anindividual optical fiber of the output bundle. This "assignment" of onefiber extending from a conventional module to one fiber of the outputbundle (which, in turn, is connected to a component remote from thesubrack) is provided by the routing module. Hence, if the assignments orconnections between individual fibers of the linking bundles that areextending from the conventional modules is to be changed, the entiresystem does not need to be disassembled. Instead, the routing module canbe replaced with a new routing module incorporating the desiredassignments.

The present invention also provides an improved method of connectingoptical signals from one optical fiber bundle or one module to an outputoptical fiber bundle or an output module. The method comprises the stepsof providing a subrack, attaching at least one routing module to thesubrack and attaching at least one conventional module to the subrack.The conventional module and routing module are linked by a linkingoptical fiber bundle as discussed above. An output fiber optical bundleis attached to an output port of the routing module and a component oralternative module disposed remote from the subrack. The assignment ofindividual optical fibers in the linking bundle to individual opticalfibers in the output bundle is provided by the routing module. To changethe assignments, the entire system need not be disassembled. Instead,the routing module simply needs to be replaced with a new routing modulewith the appropriate or desired assignments.

BRIEF DESCRIPTION OF THE DRAWING

The invention will now be described in more detail as an exemplaryembodiment to an extent necessary for understanding with reference to afigure.

FIG. 1 is a schematic representation of the subrack according to theinvention.

DETAILED DESCRIPTION OF THE PREFFERED EMBODIMENTS

FIG. 1 reveals the outline of a subrack BGT, known per se, which is ableto accommodate a number, in particular a plurality, of modules atsubrack locations BGP provided therefor. The modules receive signals viaoptical fibers or forward signals via optical fibers. In the contextwhich is of interest here, the signals are assumed to be processed inany desired manner on the modules. Furthermore, according to theinvention the subrack accommodates a routing module RGB. Each module isdetachably connected to the routing module via a multiple-plug connectorVFS and a bundle of optical fibers. In this arrangement, a bundle ofoptical fibers, which is also called a fiber array or a fiber ribbon, isassumed to be terminated by a commercially available plug connectorwhich is able to effect a simultaneous connection or isolation of aplurality of waveguides. The bundles of optical fibers and multiple-plugconnectors which connect the modules to the routing module preferablyhave a mutually identical construction. As a result of constructionalmeasures, it may be ensured that, in the course of a procedure toconnect the two cooperating parts of a multiple-plug connector, such asfor example plug and coupling or socket, the individual waveguides of abundle of optical fibers can be connected to the correspondingwaveguides only in the assigned sense.

In summary, FIG. 1 illustrates the use of a subrack BGT thataccommodates a plurality of respective or conventional modules BGP andone routing module RBG. In the embodiment illustrated in FIG. 1, eachconventional module BGP includes one multiple-plug connector VFS and therouting module RBG includes a plurality of multiple-plug connectors VFS.Each conventional module BGP is linked or connected to the routingmodule RBG by a linking optical fiber bundle LLB that extends between amultiple-plug connector VFS of a conventional module BGP to amultiple-plug connector VFS of the routing module RBG. It will be notedthat the routing module RBG includes a plurality of input ports IP aswell as a plurality of output ports OP. The linking optical fiberbundles LLB are connected to the input ports IP of the remote module RBGwhile the output ports OP connect the remote module RBG to a device orcomponent (not shown) disposed at a remote location from the subrack BGTby way of the output optical fiber bundles shown at OLB.

In the case of one embodiment, the bundle of optical fibers belonging toone module is firmly connected to the module on the module side and isterminated on the side of the routing module by a multiple-plugconnector. In this arrangement, the multiple-plug connector is assumedto be provided on the side of the bundle of optical fibers by a plug andon the side of the routing module by a coupling cooperating with theplug or by a socket fastened directly on the routing module.

In the case of another embodiment, the bundles of optical fibers leadingto the individual modules are firmly connected to the routing module onthe side of the routing module and are terminated on the module side ineach case by a multiple-plug connector. In this arrangement, themultiple-plug connector is assumed to be provided on the side of thebundle of optical fibers by a plug and on the module side by a couplingcooperating with the plug or by a socket fastened directly on themodule.

In the case of a preferred embodiment, the individual bundles of opticalfibers are terminated at both their ends with mutually identicalmultiple-plug connectors. In this arrangement, the multiple-plugconnectors are assumed to be provided on the side of a bundle of opticalfibers by plugs and on the side of the module or of the routing moduleby in each case a coupling cooperating with the plug or by a socketfastened directly on the module or the routing module. This measureaccomplishes the effect that mutually identical connecting lines can beused between the individual modules and the routing module.

In a further refinement, the part of a multiple plug connectionterminating a bundle of optical fibers, for example the plug, is fixedin relation to its position with the subrack. This measure effects aconnection or isolation of a module to or from the associated bundle ofoptical fibers when the module is being inserted into or withdrawn fromthe subrack.

The routing module is preferably arranged at a central position insidethe subrack. If mutually identical, standardized bundles of opticalfibers are provided for a subrack, it is in this case advantageouslyfound that the length to be provided of the bundles of optical fibersreaches a minimum.

In addition to the bundles of optical fibers connected to the modules ofthe same subrack, the routing module is connected to bundles of opticalfibers which receive or transmit signals from or to devices locatedoutside the subrack under consideration. These devices can in turnthemselves be provided by subracks.

The routing module is therefore connected, via a plurality of respectivemultiple-plug connectors and bundles of optical fibers, both to modulesof the same subrack and to devices outside the subrack underconsideration. The multiple-plug connectors are preferably of mutuallyidentical construction. The bundles of optical fibers preferably havethe same number of wave-guides as one another.

The routing module has the function of assigning the connections betweenthe individual waveguides of the bundles of optical fibers connected tothe routing module. The routing module therefore assigns the individualwaveguides both between the modules of a subrack and between devicesoutside the subrack and modules of the subrack. In a simple embodiment,the assignment of the connections on the routing module is executed onlyusing waveguides. In a further embodiment, the routing module can havesplitters and/or combiners for splitting or combining optical signals.In a further refinement, the routing module can have active elements,such as for example optical amplifiers, for amplifying attenuatedoptical signals and/or for regenerating received signals or signals tobe forwarded.

In a further refinement, the routing module has a central element forthe subrack under consideration; a central element can be provided by alight source, such as for example a laser diode, which outputs clocksignals, control information or cw (continuous wave) light, that is tosay a continuous optical signal.

In a further refinement, the assignment of the connections on therouting module can be switched. Any optical switches, such as forexample LCD (liquid crystal display) elements known per se or linearpolymeric optical fibers, may be employed as switching elements.Particularly advantageous is the combination of a linear polymericoptical fiber with a thermal switch produced in the same material. Thecooperation of the linear polymeric waveguide with the thermal switchaccomplishes switchability of the assignment of the individualconnections by means of electrical control signals fed to the routingmodule. An assignment by means of electrical control signals is alsoprovided in the case of an electrically activated nonlinear polymericoptical fiber.

In the case of the subject matter of the application, it is possible fora plurality of optical signals of different wavelengths to betransmitted by wavelength division multiplexing on one waveguide of abundle of optical fibers. For the purpose of separating or combiningsuch signals, it is possible to use wavelength-selective elements, suchas for example holograms, on a module or on the routing module.

For test purposes, instead of the routing module, it is possible to plugon an analysis module on which there is arranged an evaluation anddisplay device, or which is connected to an evaluation and displaydevice arranged outside the module frame. This measure accomplishessimplified fault tracing and hence shorter elimination of faults.

We claim:
 1. A module subrack assembly comprising:a subrackaccommodating at least one routing module having a plurality of inputports and at least one output port, the subrack further accommodating aplurality of modular components, each modular component being connectedto the routing module by a linking optical fiber bundle comprising amultiple-plug connector at one end of the linking bundle that isconnected to the modular component and a multiple-plug connector at theother end of the linking bundle that is connected to an input port ofthe routing module, the output port of the routing module accommodatinga multiple-plug connector that is connected to one end of an outputoptical fiber bundle, each linking optical fiber bundle comprising aplurality of optical fibers, each output optical fiber bundle comprisinga plurality of optical fibers, each optical fiber of each linking bundleis optically connected to an optical fiber of an output bundle by therouting module.
 2. The subrack assembly of claim 1 wherein themultiple-plug connectors of the connecting optical fiber bundlesdetachably connects each said conventional modules to the routingmodule.
 3. The subrack assembly of claim 1 wherein the multiple-plugconnectors of the output optical fiber bundles is detachably connectedto the routing module.
 4. The subrack assembly of claim 1 wherein eachconventional module comprises a socket for accommodating a multiple-plugconnector.
 5. The subrack assembly of claim 1 wherein each conventionalmodule comprises a socket for accommodating a multiple-plug connector.6. The subrack assembly of claim 1 wherein the routing module isdisposed at a central installation position on the subrack.
 7. Thesubrack assembly of claim 1 wherein the routing module comprises aplurality of output ports, each of said output ports a multiple-plugconnector that is connected to one end of an output optical fiberbundle, the other end of which is connected to a device disposed remotefrom the subrack.
 8. The subrack assembly of claim 1 wherein themultiple plug connectors that are connected to the conventional modulesare also connected to the subrack.
 9. The subrack assembly of claim 1wherein the multiple plug connectors that are connected to the routingmodule are also connected to the subrack.
 10. The subrack assembly ofclaim 1 wherein the routing module connects optical fibers of thelinking bundle to optical fibers of the output bundle with opticalfibers.
 11. The subrack assembly of claim 1 wherein the routing moduleconnects optical fibers of the linking bundle to optical fibers of theoutput bundle with combiners which combine optical signals.
 12. Thesubrack assembly of claim 1 wherein the routing module connects opticalfibers of the linking bundle to optical fibers of the output bundle withsplitters which split optical signals.
 13. The subrack assembly of claim1 wherein the routing module connects optical fibers of the linkingbundle to optical fibers of the output bundle with combinationcombiners/splitters which combine and/or split optical signals.
 14. Thesubrack assembly of claim 1 wherein the routing module further comprisesat least one switch for switching the connections between the opticalfibers of the linking bundles and the optical fibers of the outputbundle.
 15. The subrack assembly of claim 1 wherein the routing modulefurther comprises at least one switch for switching the connectionsbetween the optical fibers of the linking bundles and the optical fibersof the output bundle, the switch comprising a linear polymeric waveguideand a thermal switch, the linear polymeric waveguide cooperating withthe thermal switch.
 16. The subrack assembly of claim 1 wherein therouting module further comprises at least one switch for switching theconnections between the optical fibers of the linking bundles and theoptical fibers of the output bundle, the switch comprising a non-linearpolymeric waveguide which can be activated by electrical signals. 17.The subrack assembly of claim 1 wherein the routing module furthercomprises a wavelength-selective element for separating or combineoptical signals of different wavelengths.
 18. The subrack assembly ofclaim 1 wherein the routing module further comprises means for theevaluation and display of errors.
 19. A method of connecting a pluralityof optical signals to an output optical fiber bundle, the methodcomprising the following steps:providing a subrack, attaching at leastone routing module to the subrack, the routing module comprising aplurality of input ports and at least one output port, the input andoutput ports of the routing module accommodating multiple-plugconnectors of optical fiber bundles, the routing module providing aconnection between individual optical fibers connected at an input portto individual optical fibers connected at an output port, attaching atleast one modular component to the subrack, connecting the modularcomponent to the routing module by a linking optical fiber bundlecomprising a multiple-plug connector at one end of the linking bundlethat is connected to the modular component and a multiple-plug connectorat the other end of the linking bundle that is connected to an inputport of the routing module, connecting the output port of the routingmodule to one end of an output optical fiber bundle having amultiple-plug connector.
 20. A module subrack assembly for connecting aplurality of optical fibers to one or more components disposed remotefrom the subrack, the module subrack assembly comprising:a subrackaccommodating at least one routing module having a plurality of inputports and a plurality of output ports, the subrack further accommodatinga plurality of modular components, each modular component beingconnected to the routing module by a linking optical fiber bundlecomprising a multiple-plug connector at one end of the linking bundlethat is connected to the modular component and a multiple-plug connectorat the other end of the linking bundle that is connected to an inputport of the routing module, each output port of the routing moduleaccommodating a multiple-plug connector that is connected to one end ofan output optical fiber bundle, the output bundles being connected tothe components disposed remote from the module subrack assembly, eachlinking optical fiber bundle comprising a plurality of optical fibers,each output optical fiber bundle comprising a plurality of opticalfibers, each optical fiber of each linking bundle is optically connectedto an optical fiber of an output bundle by an optical fiber disposedwithin the routing module.
 21. A module subrack assembly comprising:asubrack accommodating at least one routing module having a plurality ofinput ports and at least one output port, the subrack furtheraccommodating a plurality of modular components, each modular componentbeing connected to the routing module by a linking optical fiber bundle,the output port of the routing module being connected to one end of anoutput optical fiber bundle, each linking bundle is optically connectedto the output bundle by the routing module.
 22. The subrack assembly ofclaim 21 wherein each linking optical fiber bundle comprises a connectorat one end that is connected to the modular component and a connector atanother end that is connected to an input port of the routing module.23. The subrack assembly of claim 21 wherein each linking optical fiberbundle comprises a plurality of optical fibers, each output bundlecomprising a plurality of optical fibers, each fiber of the outputbundle being connected to at least one fiber of a linking bundle.
 24. Amethod of connecting a plurality of optical signals to an output opticalfiber bundle, the method comprising the following steps:providing asubrack, attaching at least one routing module to the subrack, therouting module comprising a plurality of input ports and at least oneoutput port, the routine module providing a connection betweenindividual optical fibers connected at an input port to individualoptical fibers connected at an output port, attaching at least onemodular component to the subrack, connecting the modular component tothe routing module by a linking optical fiber bundle comprising aconnector at one end of the linking bundle that is connected to themodular component and a connector at the other end of the linking bundlethat is connected to an input port of the routing module, connecting theoutput port of the routing module to one end of an output optical fiberbundle.
 25. A module subrack assembly for connecting a plurality ofoptical fibers to one or more components disposed remote from thesubrack, the module subrack assembly comprising:a subrack accommodatingat least one routing module having a plurality of input ports and aplurality of output ports, the subrack further accommodating a pluralityof modular components, each modular component being connected to therouting module by a linking optical fiber bundle, each output port ofthe routing module being connected to one end of an output optical fiberbundle, the output bundles being connected to the components disposedremote from the module subrack assembly.
 26. The subrack assembly ofclaim 25 wherein each linking optical fiber bundle comprising aplurality of optical fibers, each output optical fiber bundle comprisinga plurality of optical fibers, each optical fiber of each linking bundleis optically connected to an optical fiber of an output bundle by anoptical fiber disposed within the routing module.